Sensor Systems for Measuring an Interface Level in a Multi-Phase Fluid Composition

ABSTRACT

A sensor includes a resonant transducer, the resonant transducer being configured to determine the composition of an emulsion. The composition of the emulsion is determined by measuring the complex impedance spectrum values of the mixture of the emulsion and applying multivariate data analysis to the values.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to concurrently filed application Ser. No.______, titled SYSTEMS AND METHODS FOR MEASURING AN INTERFACE LEVEL IN AMULTI-PHASE FLUID COMPOSITION, filed jointly in the names of CherylSurman, William Platt, William Morris, Steven Go, Jon Dieringer andRadislav A. Potyrailo, assigned to General Electric Company, theassignee of the present invention.

TECHNICAL FIELD

The subject matter disclosed herein generally relates to sensors, andmore particularly to level sensors to determine the interface level of amulti-phase fluid composition.

BACKGROUND

Measurement of the composition of emulsions and the interface level ofimmiscible fluids is important in many applications. For example, it isimportant to characterize emulsions in oil field management. Themeasurement of the water and oil content of emulsions from individualoil wells may vary over the life of an oil field and may indicate theoverall health of a field. In the case of injection wells, it iscritical to control water quality to reduce hydrate formation andcorrosion. Characterization of the composition of the oil and watermixture (e.g., measurement of the relative proportions of oil and waterin the mixture) helps the operator improve well productivity andcapacity. The information obtained is also useful to reduceback-pressure of wells, flowline size and complexity, and thermalinsulation requirements.

Characterization of emulsions is also important in the operation ofsystems that contain fluids in a vessel (vessel systems) such as fluidprocessing systems. Vessel systems may include storage tanks, reactors,separators and desalters. Vessel systems are used in many industries andprocesses, such as the oil and gas, chemical, pharmaceutical, foodprocessing industries, among others. For example, separation of waterfrom raw oil is important to establishing production streams of oil andgas. Crude oil leaving the wellhead is both sour (contains hydrogensulfide gas) and wet (contains water). The crude leaving the wellheadmust be processed and treated to make it economically viable forstorage, processing and export. One way of treating the raw oil isthrough the use of a separator. Most separators are driven by gravityand use the density differences between individual fluid phases of oil,water, gas, and solids to accomplish the separation. Identification ofthe interface levels of these layers is critical to the control of theseparation process. Another fluid processing system wherecharacterization of emulsions and measurement of the interface level isimportant is a desalter. Desalters are used in a refinery to controloverhead corrosion downstream. In a desalter water and crude oil aremixed, inorganic salts are extracted into the water, and water is thenseparated and removed.

Finally, it is important to accurately characterize the water andsalinity in the crude oil itself at various stages of the life of theproduct from a cost standpoint. Oil is a valuable commodity andunderestimation of the water content in a typical tanker load can havesignificant cost consequences.

Wastewater management is another application where measurement andcharacterization of emulsion is important. Large quantities of oilywastewater are generated in the petroleum industry from both recoveryand refining. A key factor in controlling the oil dischargeconcentrations in wastewater is improved instrumentation for monitoringthe oil content of emulsions.

Many types of level and interface instruments have been contemplatedover the years and a subset of those have been commercialized. Amongthose are gamma-ray sensors, guided wave sensors, magnetostrictivesensors, microwave sensors, ultrasonic sensors, single platecapacitance/admittance sensors, segmented capacitance sensors, inductivesensors, and computed tomography sensors. Each of the sensors hasadvantages and disadvantages. Some of the sensors are prohibitivelyexpensive for many users. Some of the sensors may require a coolingjacket to perform at operating temperatures (above 125° C.). Someinterface instruments require a clear interface to work, which can beproblematic when working with diffuse emulsions. Some are susceptible tofouling. Other sensors do not have the ability to provide a profile ofthe tank, but rather monitor discreet points in the desalting process.Systems using electrodes are susceptible to the shorting of electrodesin high salinity applications and are susceptible to fouling. Finally,many of these systems are complex and difficult to implement.

Some existing sensor systems have used individual capacitive elements tomeasure fluid levels. A key limitation of those sensor systems is theirinability to simultaneously quantify several components in the liquid.Capacitance methods have been used to measure dielectric constant of aliquid using specially designed electrodes for capacitance measurements.These designs are limited by the need for separate types of electrodesfor capacitance measurements and for conductivity measurements. Inductorcapacitor circuits also have been used to monitor the fluid level in acontainer using an electromagnetic resonator where change in capacitancewas related to fluid level and fluid type. However, it has been theconsensus of those of ordinary skill in the art that the filling of theresonator by a conducting liquid increased the uncertainties and noisein measurements by about one order of magnitude as compared to thevalues in a non-conducting fluid such as in air. However, these methodsdo not provide accurate measurements of concentrations of individualanalytes at the limits of their minimum and maximum concentrations inthe mixture.

With existing sensor systems, no one system is capable of delivering acombination of low cost, high sensitivity, favorable signal-to-noiseratio, high selectivity, high accuracy, and high data acquisitionspeeds. Additionally no existing system has been described as capable ofaccurately characterizing or quantifying fluid mixtures where one of thefluids is at a low concentration (i.e. at their minimum and maximumlimits).

BRIEF DESCRIPTION OF THE INVENTION

The disclosure provides a technical solution to the expense, reliabilityand accuracy problems of existing level sensor systems. An electricallyresonant transducer (resonant transducer) provides a combination of lowcost, high sensitivity, favorable signal-to-noise ratio, highselectivity, high accuracy, and high data acquisition speeds. Theresonant transducer is incorporated in a robust sensor without the needfor a clear interface. The solution also provides a sensor that is lesssusceptible to fouling, particularly in applications involvingemulsions.

In accordance with one exemplary non-limiting embodiment, the disclosurerelates to a sensor having a resonant transducer configured to determinea composition of an emulsion and includes a sampling assembly and animpedance analyzer.

In another embodiment, the disclosure relates to a system including afluid processing system; a fluid sampling assembly; and a resonantsensor system coupled to the fluid sampling assembly.

In another embodiment, the disclosure relates to a method for measuringa level of a mixture of fluids in a vessel. The method includes thesteps of detecting a signal from a resonant sensor system at a pluralityof locations in the vessel; converting each signal to values of thecomplex impedance spectrum for the plurality of locations; storing thevalues of the complex impedance spectrum and frequency values; anddetermining a fluid phase inversion point from the values of the compleximpedance spectrum.

In another embodiment, the disclosure relates to a method fordetermining a composition of a mixture of oil and water in a vessel. Themethod includes the step of determining values of the complex impedancespectrum of the mixture of oil and water as a function of a height inthe vessel with a resonant transducer. The method also includes the stepof determining a fluid phase inversion point from the values of thecomplex impedance spectrum; applying an oil phase model to the values ofthe complex impedance spectrum and conductivity values above the fluidphase inversion point, and applying a water phase model to the values ofthe complex impedance spectrum below the fluid phase inversion point.

In another embodiment, the disclosure relates to a sensor comprising aresonant transducer configured to simultaneously determine concentrationof a first and a second component of an emulsion.

In another embodiment, the disclosure relates to a sensor having aresonant transducer configured to determine a composition of anemulsion.

In another embodiment, the disclosure relates to a sensor system havinga resonant transducer configured to determine a composition of anemulsion. The sensor system includes a sampling assembly and animpedance analyzer.

In another embodiment, the disclosure relates to a method fordetermining a composition of a mixture of a first fluid and a secondfluid in a vessel. The determination of the composition is accomplishedby determining, with a sensor system, a set of complex impedancespectrum values of the mixture of the first fluid and the second fluidas a function of a height in the vessel. The method includes the step ofdetermining a fluid phase inversion point from the set of compleximpedance spectrum values. The method also includes the steps ofapplying a phase model of the first fluid to the set of compleximpedance spectrum values above the fluid phase inversion point, andapplying a phase model of the second fluid to the set of compleximpedance spectrum values below the fluid phase inversion point.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present disclosure will be apparentfrom the following more detailed description of the preferredembodiment, taken in conjunction with the accompanying drawings whichillustrate, by way of example, the principles of certain aspects of thedisclosure.

FIG. 1 is a schematic of a non-limiting embodiment of a resonant sensorsystem.

FIG. 2 is a non-limiting illustration of the operation of a resonanttransducer.

FIG. 3 is an example of a measured complex impedance spectrum used formultivariate analysis.

FIG. 4 illustrates an embodiment of a two-dimensional resonanttransducer.

FIG. 5 illustrates an embodiment of a three-dimensional resonanttransducer.

FIG. 6 is a schematic electrical diagram of the equivalent circuit of athree-dimensional resonant transducer.

FIG. 7 is a chart illustrating the Rp response of a resonant transducerto varying mixtures of oil and water.

FIG. 8 is a chart illustrating the Cp response of a resonant transducerto varying mixtures of oil and water.

FIG. 9 is a partial cutaway side view of an embodiment of a resonanttransducer assembly.

FIG. 10 is a schematic diagram of an embodiment of a fluid processingsystem.

FIG. 11 is a schematic diagram of an embodiment of a desalter.

FIG. 12 is a schematic diagram of an embodiment of a separator.

FIG. 13 is a chart illustrating the frequency (Fp) response of athree-dimensional resonant transducer to increasing concentrations ofoil-in-water and water-in-oil emulsions.

FIG. 14 is a chart illustrating the frequency (Fp) response of atwo-dimensional resonant transducer to increasing concentrations ofoil-in-water and water-in-oil emulsions.

FIG. 15 is a flow chart of an embodiment of a method for determining thecomposition of an oil and water mixture as a function of height.

FIG. 16 is a chart illustrating data used to determine a fluid phaseinversion point and conductivity.

FIG. 17 is a chart illustrating the results of an analysis of theexperimental data of an embodiment of a resonant sensor system.

FIG. 18 is a chart illustrating test results of a resonant sensor systemin a simulated desalter.

FIG. 19 is an embodiment of a display of a data report from a resonantsensor system.

FIG. 20 is a flowchart of an embodiment of a method for determining thelevel of a fluid in a vessel.

FIG. 21 is a block diagram of a non-limiting representative embodimentof a processor system for use in a resonant sensor system.

DETAILED DESCRIPTION OF THE INVENTION

As discussed in detail below, embodiments of the present inventionprovide low cost systems for reliably and accurately measuring the fluidlevel in a fluid processing vessel. A resonant sensor system provideseffective and accurate measurement of the level of the transition oremulsion layer through the use of a resonant transducer such as aninductor-capacitor-resistor structure (LCR) multivariable resonanttransducer and the application of multivariate data analysis applied tothe signals from the transducer. The resonant sensor system alsoprovides the ability to determine the composition of water and oilmixtures, oil and water mixtures and, where applicable, the emulsionlayer.

The resonant transducer includes a resonant circuit and a pick up coil.The electrical response of the resonant transducer immersed in a fluidis translated into simultaneous changes to a number of parameters. Theseparameters may include the complex impedance response, resonance peakposition, peak width, peak height and peak symmetry of the impedanceresponse of the sensor antenna, magnitude of the real part of theimpedance, resonant frequency of the imaginary part of the impedance,antiresonant frequency of the imaginary part of the impedance,zero-reactance frequency, phase angle, and magnitude of impedance, andothers as described in the definition of the term sensor “spectralparameters.” These spectral parameters may change depending upon thedielectric properties of the surrounding fluids. The typicalconfiguration of a resonant transducer may include an LCR resonantcircuit and an antenna. The resonant transducer may operate with apickup coil connected to the detector reader (impedance analyzer) wherethe pickup coil provides excitation of the transducer and detection ofthe transducer response. The resonant transducer may also operate whenthe excitation of the transducer and detection transducer response isperformed when the transducer is directly connected to the detectorreader (impedance analyzer).

A resonant transducer offers a combination of high sensitivity,favorable signal-to-noise ratio, high selectivity, high accuracy, andhigh data acquisition speeds in a robust sensor without the need foroptical transparency of the analyzed fluid and the measurement flowpath. Instead of conventional impedance spectroscopy that scans across awide frequency range (from a fraction of Hz to tens of MHz or GHz) aresonant transducer is used to acquire a spectrum rapidly and with highsignal-to-noise across only a narrow frequency range. The sensingcapability is enhanced by putting the sensing region between theelectrodes that constitute a resonant circuit. As implemented in a fluidprocessing system such as a desalter or a separator, the resonant sensorsystem may include a sampling assembly and a resonant transducer coupledto the fluid sampling assembly. The resonant sensor system implements amethod for measuring the level of a mixture of fluids in a vessel, andmay also implement a method for determining the composition of a mixtureof oil and water in a vessel. The resonant transducers are capable ofaccurately quantifying individual analytes at their minimum and maximumlimits. The resonant sensor system is able to determine the compositionof fluid mixtures even when one of the fluids is at a low concentration.

A nonlimiting examples of fluid processing systems include reactors,chemical reactors, biological reactors, storage vessels, containers, andothers known in the art.

Illustrated in FIG. 1 is a schematic of an embodiment of a resonantsensor system 11. The resonant sensor system 11 includes a resonanttransducer 12, a sampling assembly 13, and an impedance analyzer(analyzer 15). The analyzer 15 is coupled to a processor 16 such as amicrocomputer. Data received from the analyzer 15 is processed usingmultivariate analysis, and the output may be provided through a userinterface 17. Analyzer 15 may be an impedance analyzer that measuresboth amplitude and phase properties and correlates the changes inimpedance to the physical parameters of interest. The analyzer 15 scansthe frequencies over the range of interest (i.e., the resonant frequencyrange of the LCR circuit) and collects the impedance response from theresonant transducer 12.

As shown in FIG. 2, resonant transducer 12 includes an antenna 20disposed on a substrate 22. The resonant transducer may be separatedfrom the ambient environment with a dielectric layer 21. In someembodiments, the thickness of the dielectric layer 21 may range from 2nm to 50 cm, more specifically from 5 nm to 20 cm; and even morespecifically from 10 nm to 10 cm. In some applications the resonanttransducer 12 may include a sensing film deposited onto the transducer.In response to environmental parameters an electromagnetic field 23 maybe generated in the antenna 20 that extends out from the plane of theresonant transducer 12. The electromagnetic field 23 may be affected bythe dielectric property of an ambient environment providing theopportunity for measurements of physical parameters. The resonanttransducer 12 responds to changes in the complex permittivity of theenvironment. The real part of the complex permittivity of the fluid isreferred to as a “dielectric constant”. The imaginary part of thecomplex permittivity of the fluid is referred to as a “dielectric lossfactor”. The imaginary part of the complex permittivity of the fluid isdirectly proportional to conductivity of the fluid.

Measurements of fluids can be performed using a protecting layer thatseparates the conducting medium from the antenna 20. Response of theresonant transducer 12 to the composition of the fluids may involvechanges in the dielectric and dimensional properties of the resonanttransducer 12. These changes are related to the analyzed environmentthat interacts with the resonant transducer 12. The fluid-inducedchanges in the resonant transducer 12 affect the complex impedance ofthe antenna circuit through the changes in material resistance andcapacitance between the antenna turns.

For selective fluid characterization using a resonant transducer 12, thecomplex impedance spectra of the sensor antenna 20 are measured as shownin FIG. 3. At least three data points of impedance spectra of theemulsion are measured. Better results may be achieved when at least fivedata points of the impedance spectra of the emulsion are measured. Nonlimiting examples of number of measured data points are 8, 16, 32, 64,101, 128, 201, 256, 501, 512, 901, 1024, 2048 data points. Spectra maybe measured as a real part of impedance spectra or an imaginary part ofimpedance spectra or both parts of impedance spectra. Non-limitingexamples of LCR resonant circuit parameters include impedance spectrum,real part of the impedance spectrum, imaginary part of the impedancespectrum, both real and imaginary parts of the impedance spectrum,frequency of the maximum of the real part of the complex impedance (Fp),magnitude of the real part of the complex impedance (Zp), resonantfrequency (F1) and its magnitude (Z1) of the imaginary part of thecomplex impedance, and anti-resonant frequency (F2) and its magnitude(Z2) of the imaginary part of the complex impedance.

Additional parameters may be extracted from the response of theequivalent circuit of the resonant transducer 12. Non-limiting examplesof the resonant circuit parameters may include quality factor ofresonance, zero-reactance frequency, phase angle, and magnitude ofimpedance of the resonance circuit response of the resonant transducer12. Applied multivariate analysis reduces the dimensionality of themulti-variable response of the resonant transducer 12 to a single datapoint in multidimensional space for selective quantitation of differentenvironmental parameters of interest. Non-limiting examples ofmultivariate analysis tools are canonical correlation analysis,regression analysis, nonlinear regression analysis, principal componentsanalysis, discriminate function analysis, multidimensional scaling,linear discriminate analysis, logistic regression, and/or neural networkanalysis. By applying multivariate analysis of the full compleximpedance spectra or the calculated spectral parameters, quantitation ofanalytes and their mixtures with interferences may be performed with aresonant transducer 12. Besides measurements of the complex impedancespectra parameters, it is possible to measure other spectral parametersrelated to the complex impedance spectra. Examples include, but are notlimited to, S-parameters (scattering parameters) and Y-parameters(admittance parameters). Using multivariate analysis of data from thesensor, it is possible to achieve simultaneous quantitation of multipleparameters of interest with a single resonant transducer 12.

A resonant transducer 12 may be characterized as one-dimensional,two-dimensional, or three-dimensional. A one-dimensional resonanttransducer 12 may include two wires where one wire is disposed adjacentto the other wire and may include additional components.

Shown in FIG. 4 is a two-dimensional resonant transducer 25 having atransducer antenna 27. The two-dimensional resonant transducer 25 is aresonant circuit that includes an LCR circuit. In some embodiments, thetwo-dimensional resonant transducer 25 may be coated with a sensing film21 applied onto the sensing region between the electrodes. Thetransducer antenna 27 may be in the form of coiled wire disposed in aplane. The two-dimensional resonant transducer 25 may be wired orwireless. In some embodiments, the two-dimensional resonant transducer25 may also include an IC chip 29 coupled to transducer antenna 27. TheIC chip 29 may store manufacturing, user, calibration and/or other data.The IC chip 29 is an integrated circuit device and it includes RF signalmodulation circuitry that may be fabricated using a complementarymetal-oxide semiconductor (CMOS) process and a nonvolatile memory. TheRF signal modulation circuitry components may include a diode rectifier,a power supply voltage control, a modulator, a demodulator, a clockgenerator, and other components.

Sensing is performed via monitoring of the changes in the compleximpedance spectrum of the two-dimensional resonant transducer 25 asprobed by the electromagnetic field 23 generated in the transducerantenna 27. The electromagnetic field 23 generated in the transducerantenna 27 extends out from the plane of the two-dimensional resonanttransducer 25 and is affected by the dielectric property of the ambientenvironment, providing the opportunity for measurements of physical,chemical, and biological parameters.

Shown in FIG. 5 is a three-dimensional resonant transducer 31. Thethree-dimensional resonant transducer 31 includes a top winding 33 and abottom winding 35 coupled to a capacitor 37. The top winding 33 iswrapped around an upper portion of a sampling cell 39 and the bottomwinding 35 is wrapped around a lower portion of the sampling cell 39.The sampling cell 39 may, for example, be made of a material resistantto fouling such as Polytetrafluoroethylene (PTFE), a syntheticfluoropolymer of tetrafluoroethylene.

The three-dimensional resonant transducer 31 utilizes mutual inductanceof the top winding 33 to sense the bottom winding 35. Illustrated inFIG. 6 is an equivalent circuit 41, including a current source 43, R0resistor 45, C0 capacitor 47, and L0 inductor 49. The equivalent circuit41 also includes L1 inductor 51, R1 resistor 53 and C1 capacitor 55. Thecircuit also includes Cp capacitor 57 and Rp resistor 59. The circledportion of the equivalent circuit 41 shows a sensitive portion 61 thatis sensitive to the properties of the surrounding test fluid. A typicalRp response and Cp response of resonant a transducer 12 to varyingmixtures of oil and water are shown in FIGS. 7 and 8 respectively.

The three-dimensional resonant transducer 31 may be shielded as shown inFIG. 9. A resonant transducer assembly 63 includes a radio frequencyabsorber (RF absorber layer 67) surrounding the sampling cell 39, topwinding 33, and bottom winding 35. A spacer 69 may be providedsurrounded by a metal shield 71. The metal shield 71 is optional, and isnot part of the transducer 31. The metal shield 71 allows operationinside or near metal objects and piping, reduces noise, and creates astable environment such that any changes in the sensor response isdirectly due to changes in the test fluid. In order to successfullyencapsulate the sensor in a metal shield 71 the RF absorber layer 67 maybe placed between the sensor and the metal shield 71. This prevents theRF field from interacting with the metal and quenching the response ofthe sensor. The metal shield 71 may be wrapped with a cover 73 ofsuitable material. The RF absorber layer 67 can absorb electromagneticradiation in different frequency ranges with non-limiting examples inthe kilohertz, megahertz, gigahertz, terahertz frequency rangesdepending on the operation frequency of the transducer 31 and thepotential sources of interference. The absorber layer 67 can be acombination of individual layers for particular frequency ranges so thecombinations of these individual layers provide a broader spectral rangeof shielding.

Fouling of the resonant sensor system 11 may be reduced by providing theresonant transducer 12 with a geometry that enables resonant transducer12 to probe the environment over the sample depth perpendicular to thetransducer ranging from 0.1 mm to 1000 mm. Signal processing of thecomplex impedance spectrum reduces the effects of fouling over thesample depth.

As shown in FIG. 10, the resonant sensor system 11 may be used todetermine the level and composition of fluids in a fluid processingsystem 111. Fluid processing system 111 includes a vessel 113 with asampling assembly 115 and a resonant sensor system 11. The resonantsensor system 11 includes at least one resonant transducer 12 coupled tothe sampling assembly 115. Resonant sensor system 11 also includes ananalyzer 15 and a processor 16.

In operation, a normally immiscible combination of fluids enters thevessel through a raw fluid input 123. The combination of fluids mayinclude a first fluid and a second fluid normally immiscible with thefirst fluid. As the combination of fluids is processed, the combinationof fluids is separated into a first fluid layer 117, and a second fluidlayer 119. In between the first fluid layer 117 and second fluid layer119, there may be a rag layer 121. After processing, a first fluid maybe extracted through first fluid output 125, and a second fluid may beextracted through second fluid output 127. The resonant sensor system 11is used to measure the level of the first fluid layer 117, the secondfluid layer 119 and the rag layer 121. The resonant sensor system 11 mayalso be used to characterize the content of the first fluid layer 117,the second fluid layer 119 and the rag layer 121.

An embodiment of a fluid processing system 111 is a desalter 141illustrated in FIG. 11. The desalter 141 includes a desalter vessel 143.Raw oil enters the desalter 141 through crude oil input 145 and is mixedwith water from water input 147. The combination of crude oil and waterflows through mixing valve 149 and into the desalter vessel 143. Thedesalter 141 includes a treated oil output 151 and a wastewater output153. Disposed within the desalter vessel 143 are an oil collectionheader 155 and a water collection header 157. Transformer 159 andtransformer 161 provide electricity to top electrical grid 163 andbottom electrical grid 165. Disposed between top electrical grid 163 andbottom electrical grid 165 are emulsion distributors 167.

In operation, crude oil mixed with water enters the desalter vessel 143and the two fluids are mixed and distributed by emulsion distributors167 thereby forming an emulsion. The emulsion is maintained between thetop electrical grid 163 and the bottom electrical grid 165. Saltcontaining water is separated from the oil/water mixture by the passagethrough the top electrical grid 163 and bottom electrical grid 165 anddrops towards the bottom of the desalter vessel 143 where it iscollected as waste water.

Control of the level of the emulsion layer and characterization of thecontents of the oil-in-water and water-in-oil emulsions is important inthe operation of the desalter 141. Determination of the level of theemulsion layer may be accomplished using a sampling assembly such as atry-line assembly 169 coupled to the desalter vessel 143 and having atleast one resonant transducer 12 disposed on try-line output conduit172. The resonant transducer 12 may be coupled to a data collectioncomponent 173. In operation, the resonant transducer 12 is used tomeasure the level of water and the oil and to enable operators tocontrol the process. The try-line assembly 169 may be a plurality ofpipes open at one end inside the desalter vessel 143 with an open endpermanently positioned at the desired vertical position or level in thedesalter vessel 143 for withdrawing liquid samples at that level. Thereare generally a plurality of sample pipes in a processing vessel, eachwith its own sample valve, with the open end of each pipe at a differentvertical position inside the unit, so that liquid samples can bewithdrawn from a plurality of fixed vertical positions in the unit.Another approach to measuring the level of the emulsion layer is to usea swing arm sampler. A swing arm sampler is a pipe with an open endinside the desalter vessel 143 typically connected to a sampling valveoutside the unit. It includes an assembly used to change the verticalposition of the open end of the angled pipe in the desalter 141, byrotating it, so that liquid samples can be withdrawn (or sampled) fromany desired vertical position.

Another method to measure the level of the oil and water is to disposeat least one resonant transducer 12 on a dipstick 175. A dipstick 175may be a rod with a resonant transducer 12 that is inserted into thedesalter vessel 143. Measurements are made at a number of levels.Alternately, the dipstick 175 may be a stationary rod having a pluralityof multiplexed resonant transducers 12. The resonant transducer 12 maybe coupled to a data collection component 179 that collects data fromthe various readings for further processing.

Another embodiment of a fluid processing system 111 is a separator 191illustrated in FIG. 12. The separator 191 includes a separator vessel193 having an input conduit 195 for crude oil. Crude oil flowing frominput conduit 195 impacts an inlet diverter 197. The impact of the crudeoil on the inlet diverter 197 causes water particles to begin toseparate from the crude oil. The crude oil flows into the processingchamber 199 where it is separated into a water layer 201 and an oillayer 203. The crude oil is conveyed into the processing chamber 199below the oil/water interface 204. This forces the inlet mixture of oiland water to mix with the water continuous phase in the bottom of thevessel and rise through the oil/water interface 204 thereby promotingthe precipitation of water droplets which are entrained in the oil.Water settles to the bottom while the oil rises to the top. The oil isskimmed over a weir 205 where it is collected in oil chamber 207. Watermay be withdrawn from the system through a water output conduit 209 thatis controlled by a water level control valve 211. Similarly oil may bewithdrawn from the system through an oil output conduit 213 controlledby an oil level control valve 215. The height of the oil/water interfacemay be detected using a try-line assembly 217 having at least oneresonant transducer 12 disposed in a try-line output conduit 218 andcoupled to a data processor 221. Alternately a dip stick 223 having atleast one resonant transducer 12 coupled to a processor 227 may be usedto determine the level of the oil/water interface 204. The determinedlevel is used to control the water level control valve 211 to allowwater to be withdrawn so that the oil/water interface is maintained atthe desired height.

The following examples are given by way of illustration only and are notintended as a limitation of the scope of this disclosure. A model systemof heavy mineral oil, tap water and detergent was used to carry outstatic tests for various designs of resonant transducer 12. The level ofdetergent was kept constant for all of the mixtures.

EXAMPLE 1

In the case of the three-dimensional resonant transducer 31 disposed ona try-line or swing arm sampling assembly 13, different compositions ofoil and water were poured into a sample cell with the three-dimensionalresonant transducer 31 wound around the outside of the sample cell. FIG.13 shows the try-line/swing arm response in terms of Fp (frequency shiftof the real impedance) as oil concentration increases. The calculateddetection limit of the composition of oil in oil-in-water emulsions(FIG. 13 part A) is 0.28% and of oil in water-in-oil emulsions (FIG. 13part B) is 0.58%.

EXAMPLE 2

In the case of the two-dimensional resonant transducer 25, thetwo-dimensional resonant transducer 25 was immersed in differentcompositions of oil and water. FIG. 14 shows the response of atwo-dimensional resonant transducer 25 (2 cm circular) in terms of Fp(frequency shift of the real impedance) as oil concentration increases.The calculated detection limit of the composition of oil in oil-in-wateremulsions (FIG. 14 part A) is 0.089% and of oil in water-in-oilemulsions (FIG. 14 part B) is 0.044%. This example illustrates thatsmall concentrations of one fluid mixed large concentrations of anotherfluid can be measured with a high degree of accuracy.

EXAMPLE 3

The model system was loaded with 250 mL of mineral oil and treated withdetergent at a concentration of 1 drop per 50 mL (5 drops). The mineraloil was stirred and injected through the sensor and the impedancespectra are recorded. Small additions of water were added with constantsalinity and same detergent treatment. After the water volume exceeded66% or 500 mL of water, the system was cleaned and the experiment isrepeated with different salinity waters. The multivariate response ofthe two-dimensional resonant transducer 25 was sensitive to changes incomposition and conductivity at all levels in the test vessel of themodel system. Although the effect of conductivity and composition aresomewhat convoluted, the fact that the sensor monitors a compositiongradient allows the data analysis procedure to deconvolute theseeffects.

FIG. 15 is a generalized process diagram illustrating a method 261 fordetermining the composition of an oil and water mixture as a function ofheight.

In step 263 data (a set of LCR resonant circuit parameters) is collectedas a function of height from top to bottom (in the lab, this issimulated by starting with 100% oil and gradually adding water).

In step 265 the conductivity of water using calibration is determined At100% water, the multivariate response is compared to a calibration forwater conductivity.

In step 267 the fluid phase inversion point is determined using Zparameters.

In step 269 the Z parameters are combined with conductivity and fluidphase data.

In step 271 an oil phase model is applied. The oil phase model is a setof values correlating measured frequency values, impedance values andconductivity values to oil content in an oil and water mixture.

In step 273 a water phase model is applied. The water phase model is aset of values correlating measured frequency values, impedance valuesand conductivity values to water content in a water and oil mixture.

In step 275 the composition as a function of height is determined usingthe conductivity and the fluid phase inversion point as input parametersin the multivariate analysis and a report is generated.

FIG. 16 shows the raw impedance (Zp) vs. frequency (Fp) data for aprofile containing 0-66% water from right to left. At approximately 8.12MHz, the water content is high enough (˜25%) to induce fluid phaseinversion from oil to water continuous phase. This is apparent from thedrastic change in Zp due to the increased conductivity of the test fluidin water continuous phase. An oil continuous phase model is applied toany data points to the right of the fluid phase inversion and a watermodel to the left. Additionally, a calibration is applied to theendpoint to determine the conductivity of the water, which in this casewas 2.78 mS/cm.

FIG. 17 shows the results of an analysis of the experiment data from anembodiment of a three-dimensional resonant sensor system illustrated thecorrelation between the actual and predicted values of oil in water andwater in oil and the residual errors of prediction based on developedmodel. Part A of the chart plots the actual and predicted values of oilin water. Part B of the chart plots the actual and predicted values ofwater in oil. In part A, the data points were modeled separately fromthe data points in part B (water continuous phase). Parts C and D of thechart plot the residual error between the actual and predicted values ofoil in water and water in oil respectively. Generally, the residualerror was less than 0.5% when the actual percentage of oil is between 0%to 60%. The residual error was less than 0.04% when the actualpercentage of oil is between 70% to 100%. At the fluid phase inversionthe residual error increases up to 10% where prediction capability isdifficult due to fluctuations in the composition of the test fluid inthe dynamic test rig. The prediction capability of the sensor willimprove at compositions >66% water with more training data.

FIG. 18 illustrates the results obtained in a simulated desalter. Thechart shows a profile developed by plotting the composition as afunction of time. To simulate the sampling using a swing arm that isslowly rotated through the rag layer, a test rig was operated such thatthe composition of the test fluid was slowly modulated with time byadding small additions of water.

FIG. 19 is an illustration of the expected level of reporting from thesensor data analysis system. The end user will be shown a plot thatdisplays a representation of the composition as a function of height inthe desalter, the level of fluid phase inversion, and the width of therag layer. On the left are fluid phase indicators (black—oil, gray—oilcontinuous, cross hatched—water continuous, white—water) that indicatethe percent water/height curve. The height of the rag layer is the sumof the water continuous and oil continuous regions. The level of detailindicated will allow the operator of the desalter to optimize the feedrate of chemicals into the process, provide more detailed feedback onthe performance of a fluid processing system, and highlight processupsets that may cause damage to downstream process infrastructure.

Illustrated in FIG. 20 is a method 281 for measuring the level of amixture of fluids in a vessel 113.

In step 283, the method 281 may detect signals (a set of signals) from aresonant sensor system 11 at a plurality of locations in a vessel. Thesignals are generated by a resonant transducer 12 immersed in themixture of fluids. The resonant transducer 12 generates a set oftransducer signals corresponding to changes in dielectric properties ofthe resonant transducer 12, and the signals are detected by an analyzer15.

In step 285, the method 281 may convert the signals to a set of valuesof the complex impedance spectrum for the plurality of locations. Theconversion is accomplished using multivariate data analysis.

In step 287, the method 281 may store the values of the compleximpedance spectrum.

In step 289, the method 281 may determine if a sufficient number oflocations have been measured.

In step 291, the method 281 may change the resonant transducer 12 beingread (or the location of the resonant transducer 12) if an insufficientnumber of locations have been measured.

In step 293, the method 281 may determine the fluid phase inversionpoint if a sufficient number of locations has been measured. The fluidphase inversion point is determined from the values of the compleximpedance spectrum by identifying a drastic change in the impedancevalues.

In step 295, the method 281 may assign a value for the interface levelbased on the fluid phase inversion point.

FIG. 21 is a block diagram of non-limiting example of a processor system810 that may be used to implement the apparatus and methods describedherein. As shown in FIG. 21, the processor system 810 includes aprocessor 812 that is coupled to an interconnection bus 814. Theprocessor 812 may be any suitable processor, processing unit ormicroprocessor. Although not shown in FIG. 21, the processor system 810may be a multi-processor system and, thus, may include one or moreadditional processors that are identical or similar to the processor 812and that are communicatively coupled to the interconnection bus 814.

The processor 812 of FIG. 21 is coupled to a chipset 818, which includesa memory controller 820 and an input/output (I/O) controller 822. As iswell known, a chipset typically provides I/O and memory managementfunctions as well as a plurality of general purpose and/or specialpurpose registers, timers, etc. that are accessible or used by one ormore processors coupled to the chipset 818. The memory controller 820performs functions that enable the processor 812 (or processors if thereare multiple processors) to access a system memory 824 and a massstorage memory 825.

The system memory 824 may include any desired type of volatile and/ornon-volatile memory such as, for example, static random access memory(SRAM), dynamic random access memory (DRAM), flash memory, read-onlymemory (ROM), etc. The mass storage memory 825 may include any desiredtype of mass storage device including hard disk drives, optical drives,tape storage devices, etc.

The I/O controller 822 performs functions that enable the processor 812to communicate with peripheral input/output (I/O) devices 826 and 828and a network interface 830 via an I/O bus 832. The I/O devices 826 and828 may be any desired type of I/O device such as, for example, akeyboard, a video display or monitor, a mouse, etc. The I/O devices 826and 828 also may be The network interface 830 may be, for example, anEthernet device, an asynchronous transfer mode (ATM) device, an 802.11device, a DSL modem, a cable modem, a cellular modem, etc. that enablesthe processor system 810 to communicate with another processor system.Data from analyzer 15 may be communicated to the processor 812 throughthe I/O bus 832 using the appropriate bus connectors.

While the memory controller 820 and the I/O controller 822 are depictedin FIG. 21 as separate blocks within the chipset 818, the functionsperformed by these blocks may be integrated within a singlesemiconductor circuit or may be implemented using two or more separateintegrated circuits.

Certain embodiments contemplate methods, systems and computer programproducts on any machine-readable media to implement functionalitydescribed above. Certain embodiments may be implemented using anexisting computer processor, or by a special purpose computer processorincorporated for this or another purpose or by a hardwired and/orfirmware system, for example. Certain embodiments includecomputer-readable media for carrying or having computer-executableinstructions or data structures stored thereon. Such computer-readablemedia may be any available media that may be accessed by a generalpurpose or special purpose computer or other machine with a processor.By way of example, such computer-readable media may comprise RAM, ROM,PROM, EPROM, EEPROM, Flash, CD-ROM or other optical disk storage,magnetic disk storage or other magnetic storage devices, or any othermedium which can be used to carry or store desired program code in theform of computer-executable instructions or data structures and whichcan be accessed by a general purpose or special purpose computer orother machine with a processor. Combinations of the above are alsoincluded within the scope of computer-readable media.Computer-executable instructions comprise, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing machines to perform a certain function orgroup of functions.

Generally, computer-executable instructions include routines, programs,objects, components, data structures, etc., that perform particulartasks or implement particular abstract data types. Computer-executableinstructions, associated data structures, and program modules representexamples of program code for executing steps of certain methods andsystems disclosed herein. The particular sequence of such executableinstructions or associated data structures represent examples ofcorresponding acts for implementing the functions described in suchsteps.

Embodiments of the present disclosure may be practiced in a networkedenvironment using logical connections to one or more remote computershaving processors. Logical connections may include a local area network(LAN) and a wide area network (WAN) that are presented here by way ofexample and not limitation. Such networking environments are commonplacein office-wide or enterprise-wide computer networks, intranets and theInternet, and may use a wide variety of different communicationprotocols. Those skilled in the art will appreciate that suchnetwork-computing environments will typically encompass many types ofcomputer system configurations, including personal computers, handhelddevices, multi-processor systems, microprocessor-based or programmableconsumer electronics, network PCs, minicomputers, mainframe computers,and the like. Embodiments of the disclosure may also be practiced indistributed computing environments where tasks are performed by localand remote processing devices that are linked (either by hardwiredlinks, wireless links, or by a combination of hardwired or wirelesslinks) through a communications network. In a distributed computingenvironment, program modules may be located in both local and remotememory storage devices.

Monitoring changes of the complex impedance of the circuit and applyingchemometric analysis of the impedance spectra allows for the compositionand continuous phase of oil-in-water and water-in-oil mixtures to bepredicted with a standard error of 0.04% in 0-30% water and 0.26% in30-100% water.

Multivariate analysis tools in combination with data-rich impedancespectra allow for elimination of interferences, and transducers designedfor maximum penetration depth decreases the impact of fouling. As thepenetration depth of the resonator is extended further into the bulk ofthe fluid, surface fouling becomes less significant.

The term “analyte” includes any desired measured environmentalparameter.

The term “environmental parameters” is used to refer to measurableenvironmental variables within or surrounding a manufacturing ormonitoring system. The measurable environmental variables comprise atleast one of physical, chemical and biological properties and include,but are not limited to, measurement of temperature, pressure, materialconcentration, conductivity, dielectric property, number of dielectric,metallic, chemical, or biological particles in the proximity or incontact with the sensor, dose of ionizing radiation, and lightintensity.

The term “fluids” includes gases, vapors, liquids, and solids.

The term “interference” includes any undesired environmental parameterthat undesirably affects the accuracy and precision of measurements withthe sensor. The term “interferent” refers to a fluid or an environmentalparameter (that includes, but is not limited to temperature, pressure,light, etc.) that potentially may produce an interference response bythe sensor.

The term “transducer” means a device that converts one form of energy toanother.

The term “sensor” means a device that measures a physical quantity andconverts it into a signal which can be read by an observer or by aninstrument.

The term “multivariate data analysis” means a mathematical procedurethat is used to analyze more than one variable from a sensor responseand to provide the information about the type of at least oneenvironmental parameter from the measured sensor spectral parametersand/or to quantitative information about the level of at least oneenvironmental parameter from the measured sensor spectral parameters.

The term “resonance impedance” or “impedance” refers to measured sensorfrequency response around the resonance of the sensor from which thesensor “spectral parameters” are extracted.

The term “spectral parameters” is used to refer to measurable variablesof the sensor response. The sensor response is the impedance spectrum ofthe resonance sensor circuit of the resonant transducer 12. In additionto measuring the impedance spectrum in the form of Z-parameters,S-parameters, and other parameters, the impedance spectrum (both realand imaginary parts) may be analyzed simultaneously using variousparameters for analysis, such as, the frequency of the maximum of thereal part of the impedance (Fp), the magnitude of the real part of theimpedance (Zp), the resonant frequency of the imaginary part of theimpedance (F1), and the anti-resonant frequency of the imaginary part ofthe impedance (F2), signal magnitude (Z1) at the resonant frequency ofthe imaginary part of the impedance (F1), signal magnitude (Z2) at theanti-resonant frequency of the imaginary part of the impedance (F2), andzero-reactance frequency (Fz), frequency at which the imaginary portionof impedance is zero). Other spectral parameters may be simultaneouslymeasured using the entire impedance spectra, for example, quality factorof resonance, phase angle, and magnitude of impedance. Collectively,“spectral parameters” calculated from the impedance spectra, are calledhere “features” or “descriptors”. The appropriate selection of featuresis performed from all potential features that can be calculated fromspectra. Multivariable spectral parameters are described in U.S. patentapplication, Ser. No. 12/118,950 entitled “Methods and systems forcalibration of RFID sensors”, which is incorporated herein by reference.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.Where the definition of terms departs from the commonly used meaning ofthe term, applicant intends to utilize the definitions provided herein,unless specifically indicated. The singular forms “a”, “an” and “the”are intended to include the plural forms as well, unless the contextclearly indicates otherwise. It will be understood that, although theterms first, second, etc. may be used to describe various elements,these elements should not be limited by these terms. These terms areonly used to distinguish one element from another. The term “and/or”includes any, and all, combinations of one or more of the associatedlisted items. The phrases “coupled to” and “coupled with” contemplatesdirect or indirect coupling.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements.

What is claimed:
 1. A sensor comprising: a resonant transducerconfigured to determine a composition of an emulsion.
 2. The sensor ofclaim 1 wherein the resonant transducer comprises a resonator configuredto measure a full impedance spectrum of the resonant transducerassociated with the emulsion.
 3. The sensor of claim 1 wherein theresonant transducer is a two-dimensional resonant transducer.
 4. Thesensor of claim 1 wherein the resonant transducer is a three-dimensionalresonant transducer.
 5. The sensor claim 4 wherein the three-dimensionalresonant transducer comprises: a sampling cell; a top winding disposedaround an upper portion of the sampling cell; and a bottom windingdisposed around a lower portion of the sampling cell.
 6. The sensor ofclaim 5 comprising a radio frequency absorber disposed around the topwinding and the bottom winding.
 7. The sensor of claim 6 furthercomprising a metal shield disposed around the radio frequency absorber.8. The sensor of claim 7 further comprising a cover disposed around themetal shield.
 9. The sensor of claim 5 further comprising an absorber ofelectromagnetic radiation disposed around the top winding and the bottomwinding where the absorber absorbs electromagnetic radiation in thekilohertz, megahertz, gigahertz, and terahertz frequency rangesdepending on the operation frequency of the three-dimensional resonanttransducer and the potential source of interferences.
 10. The sensor ofclaim 5 further comprising an absorber of electromagnetic radiationdisposed around the top winding and the bottom winding where theabsorber is a combination of individual layers for particular frequencyranges.
 11. A sensor comprising a resonant transducer, the resonanttransducer being configured to simultaneously determine concentration ofa first and a second component of an emulsion.
 12. The sensor of claim11 wherein the resonant transducer is configured to measure a resonancespectrum of a real impedance of the emulsion.
 13. The sensor of claim 11wherein the resonant transducer is configured to measure at least threedata points of an impedance spectrum of the resonant transducer.
 14. Thesensor of claim 11 wherein the resonant transducer comprises a sensingregion that detects changes in capacitance and resistance of theresonant transducer.
 15. The sensor of claim 11 wherein the resonanttransducer is selected from among a group consisting of aone-dimensional resonant transducer, a two-dimensional resonanttransducer, and a three-dimensional resonant transducer.
 16. The sensorof claim 11 wherein the resonant transducer comprises a sensing regionthat detects changes in capacitance, resistance, inductance of theresonant transducer.
 17. The sensor of claim 11 where the resonanttransducer is configured to probe an environment over a sample depthperpendicular to the resonant transducer of between 0.1 mm to 1,000 mm.18. The sensor of claim 17 where effects of sensor fouling are reducedby signal processing of an impedance spectrum.
 19. The sensor of claim17 where effects of sensor fouling are reduced by transducer geometryrelated to a penetration depth of an electric field into the emulsion.20. A sensor system comprising: a resonant transducer configured todetermine a composition of an emulsion; a sampling assembly; and animpedance analyzer.
 21. The sensor system of claim 20 wherein theresonant transducer comprises a resonator configured to measure a set ofLCR resonant circuit parameters.
 22. The sensor system of claim 21wherein the set of LCR resonant circuit parameters comprise at least oneof an impedance spectrum, a real part of the impedance spectrum, animaginary part of an impedance spectrum, both real and imaginary partsof the impedance spectrum, a frequency of a maximum of the real part ofa complex impedance, a magnitude of the real part of the compleximpedance, a resonant frequency, a magnitude of the imaginary part ofthe complex impedance, and an anti-resonant frequency and a magnitude ofthe imaginary part of the complex impedance.
 23. The sensor system ofclaim 20 wherein the resonant transducer comprises a dielectric layer ofa thickness between 2 nm to 50 cm.
 24. The sensor system of claim 21wherein the impedance analyzer converts the set of LCR resonant circuitparameters to values of a complex impedance spectrum.
 25. A sensorsystem for determining a composition of a mixture of oil and water in avessel comprising: a subsystem that determines a set of compleximpedance spectrum values of the of oil at one end of the vessel and thewater at the opposite end with a resonant transducer; a subsystem thatgenerates calibration values for the sensor system for 100% oil and 100%water, respectively; a subsystem that generates a model from thecalibration values; and a subsystem that applies the model to the set ofcomplex impedance spectrum values to determine the composition.